The Oklahoma Republican congressman Markwayne Mullin has said he has no regrets about trying to enter Afghanistan on a rescue mission last month, saying that though he is “not Rambo” he would make such an attempt again “without even hesitation”.

Mullin, a former wrestler described on his own website as “a former mixed martial arts fighter with a professional record of 5-0”, told Fox News he tried to enter Afghanistan as thousands of westerners and their Afghan allies attempted to flee the Taliban.

“I wasn’t trying to go over there and be a cowboy or anything like that,” Mullin said. “It was just, ‘What else do you do when you see a problem? How do you say no if you can be an asset?’”

Afghanistan fell to the Taliban last month, nearly 20 years after the US-led invasion. The Biden administration has said it evacuated about 124,000 American citizens and Afghans deemed at risk under Islamic militant rule.

Mullin said he received requests to help thousands of people. He also said he was asked to accompany people with US military connections – “Delta [Force] guys” and “special forces” – into the war-torn country.

“I’m not Rambo,” he said. “Never pretended to be Rambo. We were surrounded by great people. Out of all the guys I was working with, I’m the low man on the totem pole. And I understood that.”

John Rambo is a character played by Sylvester Stallone in a series of action films first made in the 1980s, one concerning a mission to find Americans left behind after the Vietnam war.

Mullin said he planned to help his companions by “open[ing] the doors for them, making phone calls and being able to take in the [special immigrant visa applicants] or the [American citizens] as they came onto the plane. That was the plan.”

But, he said, “that plan changed. And it changed when we wasn’t allowed to get into Afghanistan.”

According to the Washington Post, Mullin first attempted to enter Afghanistan via Greece, only to be denied permission by the defense department.

He then reportedly called the US ambassador to Tajikistan with a request to help transport a large amount of cash into the country, saying he would be going on to Afghanistan to rescue a woman and her four children, all US citizens.

Mullin told the embassy he planned to fly to Dushanbe in Tajikistan from Tbilisi in Georgia, then to rent a helicopter. The embassy turned him down. Officials told the Post Mullin threatened the US ambassador, John Mark Pommersheim.

Mullin told Fox News: “Unfortunately, the ambassador, Pommersheim, was not helpful at all.”

Mullin’s attempts to reach Afghanistan followed an unauthorized and widely criticised visit to Kabul by a Republican congressman, Peter Meijer, and a Democrat, Seth Moulton. The two military veterans have defended their actions.

US troops completed their withdrawal from Afghanistan this week. The state department says Americans should not visit the country “due to civil unrest, armed conflict, crime, terrorism, kidnapping, and Covid-19”.

Mullin, who told Fox News he and others had estimated they had “a 50-50 chance of coming back” from their planned mission, wrote on Instagram on Wednesday that he had nonetheless helped Americans out of the country.

“I am heading home,” he wrote, without specifying where he was.

“Have we been helping get Americans out of Afghanistan? Yes. Is the mission continuing? Yes. Am I missing? No. Did I go dark for a little? Yes, because it wasn’t safe to be communicating. Am I extremely disappointed in how we (United States) left Americans behind … that would be an understatement.”

Biden and members of his administration have said between 100 and 200 US citizens remain in Afghanistan. The White House has said it will continue efforts to help any who wish to leave the country. Veteran-led rescue groups have said the official estimate overlooks hundreds of permanent legal residents with green cards.

After claiming Joe Biden was “absolutely lying to the American people about Americans and our friends being left behind”, Mullin added a hashtag: #Ordinarypeopledoingextraordinarythings.